Incandescent lamp.



E. WEINTRAUB.

INCANDESGENT LAMP.

' APPLICATION FILED 0013.2, 1908.

Patented Jan. 7, 1913.

Fig 2.

Inventor: Ezechiel Weintraub:

UNITED STATES PATENT OFFICE.

."EZEGHIEL'WEINTRAUB, OF LYNN, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

INCANDESCENT LAMP.

Improvements in Incandescent Lamps, of

which the toll-owing is a specification.

My present invention relates *to incandes cent lamps, and more particularly to lamps in which the incandescing member or filament is normally surrounded by a vaporized metal. l

According to my invention the filament is so proportioned and disposed as to-insure a long life and good efiiciency, and with freedom from danger of short circuits in thej lamp because of the presence of the mercury I by splicing in section of heat y filament or or other metallic vapor.

In the accompanying drawing, Figure 1 is an elevation of the completed lamp with port-ions broken away, and F 2 iscertain a detail.

The lamp shown in Fig. lcomprises an ordinary screw socket 1 to which is attached a protective or inclosing globe 2 normally communicating with the atmosphere through an opening 3 at the point where most lamp bulbs are sealed oft. Within this inclosing globe is an evacuated U-shaped tube 4 through which extends a filament 5 supplied with current through the usual leading in conductors 6 and 7. Sufficient mercury is introduced into this evacuated tube 4 to provide an appreciable quantity of mercury vapor therein when the filament 5 is at normal runningtemperature. When the lamp is cold this mercury condenses and forms a globule of about the size indicated at 8 in the drawing. I

I have found that if the filament 5 is of uniform cross section throughout its length, there is a tendency for the formation of a mercury arc shunting the lower or curved portion of the filament-loop. When such an Specification of Letters Patent.

Application vfiled. October 2, 1908.

Patented Jan. '7, 1913.

Serial No. 455,885.

:bility of .a mercury are between adjacent portions. This increased conductivity may be secured making the curved portion of the filament out of material of higher conductivity'than that of the legs of the filament. Or it may be secured by increasing the cross section throughout the curved portion 9, as

by locally flashing to secure a corresponding increase in diameter,

An embodiment of my invention is indicated somewhat diagrammatically by the drawings, where the curved portion 9 of the filament is shown as of higher conductivity than the straight portions and therefore operative at a lower temperature.

What I claim as new and desire to secure by Letters Patent of the United States, is:

In an incandescent lamp, the combination of a U-shaped tube, mercury therein which is more or less vaporized during operation of the lamp, and a bent filament within said tube, conforming tothe shape of said tube, the bent portion of the filament being thicker and of greater conductivity than the leg portions thereof to prevent disintegration of the filament at the bend.

In witness whereof, I have hereunto set my hand this thirtieth day of Sept, 1908.

EZECHIEL WEINTRAUB. 

